1. Field of the Invention
The invention relates generally to the transfer of signals between objects that move relative to one another and, more particularly, to RF signal transmission between the fixed base portion and the sliding portion of a slider phone using capacitive coupling that provides RF signal transmission when the slider is fully open and closed.
2. Introduction
Slider Form Factor has become increasingly popular for cell phones or portable communication devices. More applications are added into cell phones requiring more antennas for these different applications and their associated radio frequency (RF) transceiver circuits. Due to the reduction in size of these devices, it becomes more difficult to have all antennas and their associated transceiver circuits confined exclusively to one particular area of the communication device.
Placing an antenna and its associated transceiver circuit in different parts, for example an antenna in the slider part and the transceiver part in the fixed base, requires a RF signal transmission path between the slider and the fixed base. In most slider phones, a flex circuit is used to transmit base band low frequency signals. This flex circuit is not suitable for transmitting RF signal. In this situation, an additional interconnection path using a coaxial cable may be used. However, the use of coaxial cable adds to the complexity of the antenna chassis structure and also to the mechanical complexity/size of the sliding arrangement.
The patent to Phillips Et. Al. (U.S. Pat. No. 5,014,346) describes a method of rotatable inductive coupling of RF signals between a transceiver circuit and an antenna at different parts of the portable communication device. This was applicable for hinged or rotatable devices like clamshell phones or phones with a rotatable flip. While coaxial cable is good for RF signal transmission it severely complicates chassis design and adds to the mechanical complexity.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for RF signal transmission between the fixed base part and the slider part of a slider phone that does not severely complicate chassis design or add to the mechanical complexity of the phone. There is also a need for improved internal RF signal transmission that does not require electrical contact or concentric conductors between the base part and the sliding part of a slider phone.